Japan 30-Year Bond Sale in Focus as Yield Nears Record 4.155%

Japan’s 30-year government bond yield is hovering near a record high, leaving a bond auction on Sept. 3 as a key test for whether the global selloff in sovereign debt has further to run.

Japan’s 30-year yield rose to 4.155% on Sept. 3, according to Bloomberg. That left it near the highest level since the tenor was introduced in 1999. The sharp rise reflects a broader selloff in long-dated bonds worldwide, compounded by concern over Japan’s expanding fiscal stance.

Investors are now focused on the 30-year auction later in the day. Weak demand could push Japan’s long-term yields even higher and spread selling pressure to global government bond markets, including the US.

Fiscal worries are also weighing on sentiment. Prime Minister Sanae Takaichi is pursuing an active fiscal policy, while budget requests from government ministries for next year reached a record high. That has added to concern that Japan may increase bond issuance to finance additional spending. Japan’s 10-year government bond yield also recently touched 3% for the first time in 30 years.

Upward pressure on yields is also building from the monetary-policy side. Bank of Japan Governor Kazuo Ueda said at this month’s policy meeting that officials would make decisions with upside inflation risks in mind, keeping open the possibility of another rate increase. US Treasury Secretary Scott Bessent has also repeatedly emphasized in recent days that Japan needs to respond on monetary policy.

Barclays strategists said the 30-year auction would probably be somewhat weak or broadly in line with expectations. While current yield levels are not far from long-term fair value, concerns over fiscal health are still constraining demand for government bonds.

Higher long-term Japanese yields could also pressure the US Treasury market. If the gap between Japanese and US 30-year yields narrows to less than 100 basis points, Japanese bonds may look relatively more attractive, adding selling pressure to Treasuries.

“Japanese government bonds long served as an anchor for the global bond market, but that has now reversed,” Prashant Newnaha, Asia-Pacific rates strategist at TD Securities, said. “If the selloff in JGBs deepens, it could trigger a broader repricing across global bonds.”

Still, demand may hold up. The past two 30-year auctions drew relatively strong bid-to-cover ratios, and life and non-life insurers have been increasing purchases of ultra-long bonds. Even so, uncertainty over how high yields may rise is making investors wary of aggressively increasing exposure to long-dated debt.